Less Chlorine and Less Pollution Bleaching Process of Pulp Imitation Enzyme Pretreatment

A pulp bleaching and pretreatment technology, applied in the field of pulp bleaching, to achieve the effect of moderate price, small amount of pyridine, and high whiteness

Inactive Publication Date: 2011-12-07
KUNMING UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, it is a new attempt and application to combine imitation enzyme pretreatment with less toxic and less polluting chlorine-free elemental chlorine-free bleaching process to form a new elemental chlorine-free bleaching process, and there is no relevant technical report yet.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0019] In the pulp with a concentration of 5% by weight, the amount of NaOH is 3.0%, H 2 o 2 Consumption is 1.2%, metal salen consumption is 0.025%, pyridine consumption and metal salen molar ratio are 0.95: 1, O 2 The pressure is 0.17MPa, and the pulp bleaching pretreatment is controlled at a temperature of 65°C to 75°C for 4h to 5h. Then carry out subsequent elemental chlorine-free bleaching treatment. In the chlorine dioxide bleaching section, the chlorine dioxide consumption is 0.2%, the sodium hydroxide and chlorine dioxide consumption ratio is 0.9: 3, the pulp concentration is 10% during treatment, the temperature is 60° C., and the time is 0.5 hours ; In the chelation treatment section, the chelation treatment diethylenetriaminepentaacetic acid consumption is 0.50%, the pulp concentration is 10% during treatment, the temperature is 50°C, and the time is 0.9 hours; in the hydrogen peroxide bleaching section, the sodium hydroxide consumption is 0.70%, silicon The consum...

Embodiment 2

[0021] In the pulp with a concentration of 3% by weight, the amount of NaOH is 2.0%, H 2 o 2 Consumption is 1.0%, metal salen consumption is 0.02%, pyridine consumption and metal salen molar ratio are 0.90: 1, O 2 The pressure is 0.15MPa, and the pulp bleaching pretreatment is controlled at a temperature of 65°C to 75°C for 4h to 5h. Then carry out subsequent elemental chlorine-free bleaching treatment. In the chlorine dioxide bleaching section, the chlorine dioxide consumption is 0.18%, the sodium hydroxide and chlorine dioxide consumption ratio is 0.8:3, the pulp concentration is 9% during treatment, the temperature is 55°C, and the time is 0.4 hours ; In the chelation treatment section, the chelation treatment diethylenetriaminepentaacetic acid consumption is 0.45%, the pulp concentration is 9% during treatment, the temperature is 45°C, and the time is 0.8 hours; in the hydrogen peroxide bleaching section, the sodium hydroxide consumption is 0.68%, silicon The sodium acid...

Embodiment 3

[0023] In the pulp with a concentration of 7% by weight, the amount of NaOH is 4.0%, H 2 o 2 Consumption is 1.5%, metal salen consumption is 0.03%, pyridine consumption and metal salen molar ratio are 1: 1, O 2 The pressure is 0.20MPa, and the pulp bleaching pretreatment is controlled at a temperature of 65°C to 75°C for 4h to 5h. Then carry out subsequent elemental chlorine-free bleaching treatment, in the chlorine dioxide bleaching section, the chlorine dioxide consumption is 0.22%, the sodium hydroxide and chlorine dioxide consumption ratio is 1:3, the pulp concentration is 11% during treatment, the temperature is 65°C, and the time is 0.6 hours ; In the chelation treatment section, the chelation treatment diethylenetriaminepentaacetic acid consumption is 0.55%, the pulp concentration is 11% during treatment, the temperature is 55°C, and the time is 1.1 hours; in the hydrogen peroxide bleaching section, the sodium hydroxide consumption is 0.72%, silicon The sodium acid co...

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PUM

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Abstract

Pulp imitation enzyme pretreatment bleaching process with less chlorine and less pollution. The invention relates to a low-chlorine element-free chlorine-free bleaching (ECF) process for pulp imitating enzyme pretreatment, which is a novel pulp imitating enzyme pretreatment and less-pollution bleaching technology, and belongs to the technical field of papermaking. The present invention mainly comprises the following steps: ① pretreat the pulp with metal salen imitation enzyme, and carry out bleaching pretreatment on oxygen desulfated pulp under alkaline conditions by metal salen, pyridine, H2O2 and O2; ② follow-up less chlorine and less Contamination bleaching, the pulp after imitation enzyme pretreatment is then bleached in three stages consisting of a chlorine dioxide bleaching stage, a chelating stage and a hydrogen peroxide bleaching stage. The invention is simple and easy to implement, has remarkable effect, can increase the whiteness of bleached pulp, and can remarkably improve the performance of the pulp. Compared with the conventional low-chlorine bleaching process, the bleaching process of the present invention uses less chlorine. Refining times can also be reduced compared to conventional CEH bleaching.

Description

technical field [0001] The invention relates to a paper pulp imitative enzyme pretreatment bleaching process with less chlorine and less pollution, belonging to the paper pulp bleaching technology. Background technique [0002] Conventional CEH (chlorination-alkali treatment-hypochlorite bleaching) bleaching of pulp requires a high amount of chlorine for bleaching, high toxicity in wastewater, serious environmental pollution, poor pulping performance, and long refining time. Therefore, the production cost is also higher. [0003] Elemental chlorine-free bleaching has been widely used in the field of pulp bleaching. It is a less-polluting bleaching process with the advantages of good pulping performance and high whiteness. However, in the conventional elemental chlorine-free bleaching process, two or more stages are generally required in the chlorine dioxide bleaching stage, and the amount of chlorine used for bleaching and the toxicity of waste water are relatively high, wh...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): D21C9/16
Inventor 周学飞刘晶
Owner KUNMING UNIV OF SCI & TECH
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